The invention relates to grip compensating and centralizing chucks and more prticularly to such a ball chuck. Ball chucks have been used for many years and in many operations are considered highly preferable because of their ability to provide a strong, positive grip of the workpiece. However, like some other chucks, they are subject to failure or partial failure due to the small but gradual release of their grip on the workpiece. Various techniques have been developed to provide a better lock for preventing a ball chuck from inadvertently releasing or partially releasing its grip on the workpiece. A few of these have been introduced and tried. Some of these attempts to solve the problem have improved the situation but they have not solved it.
The problem is made more complex by the current trend to the use of higher chuck speeds to reduce the cutting time. As chuck speed increases, the centrifugal forces which tend to open the chuck also increase, thus, significantly impairing the reliability of such chucks. Another factor entering into the problems is that of tool pressure. Not only have modern demands required increases in the speed of the chuck, they also have increased the pressure with which the tools are applied, requiring the chuck to maintain an even more positive grip on the workpiece. All of these factors have combined to materially complicate the problem of maintaining a positive grip on the workpiece and of being certain that this grip remains constant and does not loosen during the machining operation.